Cyclone® V Device Handbook: Volume 1: Device Interfaces and Integration

ID 683375
Date 10/18/2023
Public
Document Table of Contents

3.5.1. Input Register Bank

The input register bank consists of data, dynamic control signals, and two sets of delay registers.

All the registers in the DSP blocks are positive-edge triggered and cleared on power up. Each multiplier operand can feed an input register or a multiplier directly, bypassing the input registers.

The following variable precision DSP block signals control the input registers within the variable precision DSP block:

  • CLK[2..0]
  • ENA[2..0]
  • ACLR[0]

In 18 x 19 mode, you can use the delay registers to balance the latency requirements when you use both the input cascade and chainout features.

The tap-delay line feature allows you to drive the top leg of the multiplier input, dataa_y0 and datab_y1 in 18 x 19 mode and dataa_y0 only in 27 x 27 mode, from the general routing or cascade chain.

Figure 20. Input Register of a Variable Precision DSP Block in 18 x 19 Mode for Cyclone® V DevicesThe figures show the data registers only. Registers for the control signals are not shown.


Figure 21. Input Register of a Variable Precision DSP Block in 27 x 27 Mode for Cyclone® V DevicesThe figures show the data registers only. Registers for the control signals are not shown.